Accelerating the laser-induced demagnetization of a ferromagnetic film by antiferromagnetic order in an adjacent layer

Research paper by Ivar Kumberg, Evangelos Golias, Niko Pontius, Rahil Hosseinifar, Karl Frischmuth, Ismet Gelen, Tauqir Shinwari, Sangeeta Thakur, Christian Schüssler-Langeheine, Peter Oppeneer, Wolfgang Kuch

Indexed on: 13 Aug '20Published on: 12 Aug '20Published in: arXiv - Physics - Mesoscopic Systems and Quantum Hall Effect


We study the ultrafast demagnetization of Ni/NiMn and Co/NiMn ferromagnetic/antiferromagnetic bilayer systems after excitation by a laser pulse. We probe the ferromagnetic order of Ni and Co using magnetic circular dichroism in time-resolved pump--probe resonant X-ray reflectivity. Tuning the sample temperature across the antiferromagnetic ordering temperature of the NiMn layer allows to investigate effects induced by the magnetic order of the latter. The presence of antiferromagnetic order in NiMn speeds up the demagnetization of the ferromagnetic layer, which is attributed to bidirectional laser-induced superdiffusive spin currents between the ferromagnetic and the antiferromagnetic layer.